Be bold enough (to) (4)
I believe the answer is:
dare
'be bold enough to' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for dare that I've seen before include "Challenge of courage" , "Be bold enough (to)" , "Have the courage to try something" , "Dan - - , 'Eagle' pilot" , "Be brave enough" .)